450mm FL apo anywhere?

[ollypenrice]

Hi all,

I want to make a two shooter setup with the Baby Q (FL450mm) next to a half decent little apo/semi-apo also of 450mm FL to collect Ha. In this near monochromatic filter quality does not have to be outstanding and I am not about to buy another FSQ! I can get 480mm with my Pronto and a reducer but can anyone think of a scope offering 450mm FL on the nose?

If you can, many thanks...

Olly

[Psychobilly]

How about something around 560mm with a 0.8x reducer flattener for 448mmm?

Just the first find... of a 560mm FL "APO"

http://www.teleskop-service.se/produkter/eng/scopos/start/scoposstart.html#TL805APO

http://www.astro-professional.com/html/ed_80mm-2.html

[BlueAstra]

Meade 5000 ED80 APO ? 480mm focal length, 384mm with my 0.8 reducer.

[ollypenrice]

Thanks both. I have the same FL as I'd get with the Meade already (Pronto/reducer) but the TS scope at 80 percent would indeed be as good a match as I'd ever get.

Cheers,

Olly

[shaunster]

No Olly, the best match would be two FSQ's side by side

[martin_h]

http://stargazerslounge.com/equipment-discussion/144632-double-shooter.html

[3ggman]

Brandon Master Birder. Dunno if it would be any use for what you need it for.

VERNONscope & Company Brandon Master Birder Tube Assembly with Focusing Unit

[nightvision]

Hmmm interesting idea, got me thinking... would a couple of these be any good? They seem good value at only £244 each. Fast even before using reducers. IanKingImaging's IKI 70mm F6 ED APO Refractor OTA from Ian King Imaging

Specs:

70mm F6 Multi Coated ED Doublet

1:10 Dual Speed Rotating Crayford Focuser

Mounting Bracket (Vixen/Skywatcher Compatible)

2" to 1.25" Adaptor

Length: (Dew Shield Retracted) 12"

Length: (Dew Shield Extended) 15.5"

Weight: 2kg

[ollypenrice]

Well... I have an FSQ which is as near to optical perfection as I'm likely to see in my lifetime. This matters with colour. Buy another one? at £3.5k, well...no! Buy another one to shoot near monochromatic light which makes no demand on the colour correction? No, no, no and thrice no!

Anything half decent at the right FL will do almost exactly as well as the FSQ in a tight Ha filter.

The trick is not to have two the same but to have one premium for the colour and one so-so for the optically undemanding Ha. I had an elderly Genesis which was almost as good as a friend's FSQ106 on back to back Ha. On RGB there was no comparison, the FSQ was in a different league.

But, in principle, if deciding on a really good imaging rig a fast 2-shooter has to be worth considering intsead of going for a single up market system at the same price. I depends on what you want to image.

As things stand, I may for a short time be able to show you two FSQs on a single mount... but it won't last!

Olly

[nightvision]

That's educational Olly, I now see where you are going, so taken to an extreme would an achro do the job? I saw some green filtered shots from an ST scope and they seemed very sharp.

[ollypenrice]

That's educational Olly, I now see where you are going, so taken to an extreme would an achro do the job? I saw some green filtered shots from an ST scope and they seemed very sharp.

That might be going a bit far but, you know, it might not. In principle, that is the line of my thinking but since good semi apos are not (in the scheme of things) very expensive then that would do me.

Olly